1. Technical Field:
The present invention relates in general to an improved data processing system and in particular to an improved data processing system having reduced emissions of electromagnetic energy. Still more particularly, the present invention relates to an improved data processing system outer case having reduced emissions of electromagnetic energy from apertures within the case having electronic subassemblies mounted therein.
2. Description of the Related Art:
Modern data processing systems often incorporate multiple electronic subassemblies which may be mounted in and removed from so-called "bays" or apertures within a data processing system housing. A problem which exists with such data processing systems is the amount of electromagnetic emissions which are generated by the data processing system and electronic subassemblies such as diskette drives, fixed disk drives, tape drives and optical disk readers.
The amount of electromagnetic interference or "noise" which may be emitted by a data processing system is strictly limited by government regulation. As the performance attributes of modern state-of-the-art electronic subassemblies are increased, such assemblies emit greater amounts of radio frequency noise. This is due in part to the electronic elements, such as very fast field effect transistor (FET) logic families which are utilized in such devices. While a data processing system is typically mounted within a case or housing, which is conductive and thus impermeable to radio frequency noise, such housings typically include removable panels which cover bays or apertures which may be utilized to insert electronic subassemblies such as those described above.
When such a panel is removed to insert a fixed disk drive and then replaced, the panel will block electromagnetic emissions from the device. However, certain electronic subassemblies require user access to the interior aspects of such a subassembly. For example, optical disk readers and diskette drives require an aperture which permits the operator to insert a diskette or optical disk. Such devices are typically installed within a bay or aperture within the data processing system housing and then surrounded by a plastic bezel or frame which permits the operator to insert a diskette or optical disk.
In such applications, electromagnetic energy from within the data processing system may "leak" around the diskette drive or optical disk reader through these plastic bezels and cause unacceptable levels of electromagnetic emissions in the vicinity of the data processing system.
It should therefore be apparent that a need exists for a system which permits electronic subassemblies to be mounted within apertures within a data processing system housing but which minimize or attenuates the amount of electromagnetic interference emitted from those apertures during operation of the data processing system.